Mechanical device for producing a progressively decreasing force the initial value of which is considerable



J y 1951 G. A. VANMALCOT MECHANICAL DEVICE FOR PRODUCING A PROGESSIVELY DECREASING FORCE THE INITIAL VALUE OF WHICH IS CONSIDERABLE Filed Aug. 4, 1947 4 1/ :::::::Ql"* 6 IJ'A D 2 a I [/3 P y INVENTO? u-ml 60A.

ATTORNEYS Patented July 10, 1951 MECHANICAL DEVICE FORPRODUCING A PROGRESSIVELY DECREASING FORCE I THE INITIAL SIDERABLE VALUE OF WHICH IS CON- Gustaaf Albrecht Vanmalcot, Schaerbeek-Brus- ,sels, Belgium, assignor to Socit Anonyme Minimax,

Brussels, Belgium, a Belgian company Application August 4, 1947, Serial No. 765,912

In Belgium December 10, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires December 10, 1963 3 Claims.

My present invention relates to a mechanism the object of which is to overcome a progressively decreasing force or resistance the initial value of which is considerable and which tends to the infinity.

With the above and other objects in view which will become apparent from the detailed description below the invention is shown in the drawings in which:

Fig. 1 is a diagrammatical view illustrating the principle of the invention;

Fig. 2 is a diagrammatical view illustrating the principles of the invention; and

Fig. 3 is an elevational view showing oneapplication of the new invention.

In the various views similar reference characters indicate like parts.

The invention is based (Fig. 1) on the use of four levers I, I1, I2, I 3 which are pivoted together in the shape of a parallelogram by pivots A, B, C, D of which one pivot A is carried by a fixed element S whileon pivot .C situated opposite pivot A the resistance R is acting and to B and D springs I are secured which are hooked respectively at E and E also to a fixed element which may be the element S.

Those springs exert forces F of the same magnitude at each of the points B and D.

It is a well known principle that in such an arrangement the forces F required to overcome R are substantially less than R but that they decrease at a rate which varies as the point C moves near the point A.

This is tantamount to saying that the effective force required to overcome the resistance R decreases at the rate that the point B moves away from the point D.

The values of this effective force may be determined graphically as can be seen from Fig. 2 in which the existence has been assumed of a fixed scale line EFAFE on which there is applied, at A, the fixed point of the parallelogram ABCD.

If now there is applied to points B and D forces which pass through E and E. and have values EB and ED the points B and D will move on the arc of the circle FBDF' and resultant CL will be determined by the graph shown in which CH has the same value as BG and CM the same value as DK.

If a parallelogram such as AB'C'D is considered with the operating forces B'E'- and DE, the result is that these two latter forces produce a resultant acting at the point C and having a value C'L' instead of CL for parallelogram ABCD.

.sultant, at C, of C'L' It is quite apparent that the small increase in value of force BE in relation to BE gives a rewhich is out of proportion to this relatively small increase in the forces.

If the parallelogram is still further flattened out, the resultant CL will be still further increased and will eventually tend to become infinite.

I This system permits the application at the point C (Fig. 1) of a force in the direction of A which, with two equal forces acting at B and D, will be effective along the bisection of the angle of application of the forces.

Moreover the amplitude of the displacement of C towards A may be modified by varying the length of the sides of the parallelogram, at the same time maintaining for the force applied at C the desired value at the end of the requisite displacement.

An example of practical application of the device to the operation of gas cylinders, for example containing carbonic acid gas, is illustrated diagrammatically in Fig. 3.

When the member which surmounts the gas cylinders is opened the maximum force is required at the moment when the control lever has to move the valve which is applied fluid-tightly to its seat by the pressure of the gas within the cylinder. When this initial resistance has been overcome and the gas pressure is applied against both faces of the valve, the effort required in maintaining the latter in its open position becomes a minimum.

In Fig. 3, I, I1, I2, is represents the parallelogram which is normally in the closed position. A latching lever arms the device and is maintained in this position by a retaining cable 5 which is adapted for manual or automatic control. As shown, lever 4 is mounted on axle D and grips by a notch In axle B.

Springs I are hooked at E and E to a plate 2 which is fixed to a wall 3 and are secured respectively to B and to the latching lever 4.

Under these conditions, if the cable 5 is released by these control means the lever 4 pivots, and, as a result of the tractive effort of the spring I acting at B frees the point B. The springs l cause the parallelogram to open. As a result, the point C is violently and suddenly displaced towards A, taking with it the linkage 6 and the levers 1 of the gas cylinders 8.

As the force exerted on C tends to become in finite, it is possible to open a considerable number of cylinders with a single device.

Moreover, the increase in pressure in the gas cylinders may be readily overcome, the powerof the springs and the path of the point being capable of suitable determination in this respect.

It is thought that the invention and its advantages will be understood from the foregoing description and it is apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing its material advantages, the form hereinbefore described and illustrated in the drawings being merely a preferred embodiment thereof.

What I claim is:

1. A mechanism for overcoming a progressively decreasing resistance the initial value of which is considerable comprising four levers pivoted together in the shape of a parallelogram by pivots, a fixed element upon which one of said pivots is mounted, the pivot situated opposite said first pivot having the resistance to be overcome applied thereto, springs each fixed to a fixed point applying forces of the same magnitude to each of the third and fourth pivots of said parallelogram, a latching lever mounted on one of said last named pivots having a notch to grip the other of said last named pivots, said latching lever maintaining said parallelogram normally closed, retaining means maintaining said lever in its latching position and controlling means to suspend this retaining action and to cause said parallelogram to open and to overcome said resistance.

2. A mechanism for overcoming a progressively decreasing resistance the initial value of which is considerable comprising four levers pivoted together in the shape of a parallelogram by pivots, a fixed element upon which one of said pivots is mounted, the pivot situated opposite said first pivot having the resistance to be overcome applied thereto, springs each fixed to a fixed point applying forces of the same magnitude to each of the third and fourth pivots of said parallelogram, a latching lever mounted on one of said last named pivots having a notch to grip the other of said last named pivots, said latching lever maintaining said parallelogram normally closed, a retaining cable whereby said lever is maintained in its latching position and control means whereby said cable is released, the latching lever is caused to pivot and the parallelogram is caused to open.

3. A mechanism for overcoming a progressively decreasing resistance the initial value of which is considerable comprising four levers pivoted together in the shape of a parallelogram by pivots, a fixed element upon which one of said pivots is mounted, the pivot situated opposite said first pivot having the resistance to be overcome applied thereto, springs each fixed to a fixed point applying forces of the same magnitude to each of the third and fourth pivots of said parallelogram, the fixed points to which said springs are attached being in one and the same alignment with said fixed point of the parallelogram, a latching lever mounted on one of said last named pivots having a notch to grip the other of said last named pivots, said latching lever maintainingsaid parallelogram normally closed, retaining means maintaining said lever in its latching position and controlling means to suspend this retaining action and to cause said parallelogram to open and to overcome said resistance.

GUSTAAF ALBRECHT VANMALCOI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 726,008 Wennas Apr. 21, 1903 1,921,173 St. Maur Aug. 8, 1933 1,965,845 Mapes July 10, 1934 2,243,581 Smith May 27, 1941 FOREIGN PATENTS Number Country Date 19,972 Great Britain Sept. 20, 1898 

